Artificial posterior teeth

ABSTRACT

A pair of artificial posterior teeth having co-engageable occlusal surfaces, the upper tooth having an incising ridge on its occlusal surface extending in mesial-distal direction and the lower tooth being concaved in a buccal-lingual direction on its occlusal surface and having sulci which are closed at one end and open at the other, whereby said incising ridge, when moving in lteral excursion in one direction effects shearing engagement with the closed ends of said sulci and when moving in the opposite direction, sluices sheared food from the open ends of said sulci.

Sept. i, W73

Unite States Patent [1 1 Warren ARTIFICIAL POSTERIOR TEETH PrimaryExaminer-Russell R. Kinsey Assistant Examiner.l. Q. Lever AtzorneyC.Hercus Just Inventor: William 0. Warren, York, Pa.

[57] ABSTRACT A pair of artificial posterior teeth having co-engageable[22] Filed:

[ PP NOJ 204,025 occlusal surfaces, the upper tooth having an incisingridge on its occlusal surface extending in mesial-distal direction andthe lower tooth being concaved in a buc- 32 8 U A6 13/40 cal-lingualdirection on its occlusal surface and having Field of 32/8 2 sulci whichare closed one and the 0th,

whereby said incisingridge, when moving in lteral exu u L n I ll] 2 00555 [ll cursion in one direction effects shearing engagement with theclosed ends of said sulci and when moving in References Cited UNITEDSTATES PATENTS the opposite direction, sluices sheared food from the2,548,956 32/8 open ends f Said sulci, 3,305,926 32/8 4 Claims, 9Drawing; Figures Patented Sept. 4, 1973 2 Sheets-Sheet 1 FIG.

FIG.

INVENTOR WILLIAM O. WARREN FIG.

ATTORNEY Patented Sept. 4, 1973 2 Sheets-Sheet 2 FIG.

FIG. 8

INVENTOR WILLIAM O. WARREN l I/ n I ATTORNEY ARTIFICIAL POSTERIOR TEETHBACKGROUND OF THE INVENTION In a natural dentition, each tooth has itsown shockabsorbing membrance which surrounds the root of the tooth andby which it is retained in operative position within the human gums. Inview of this, when greater pressure is exerted against one or moreindividual teeth, or a limited group of successive tooth, such pres sureis not transmitted to the other teeth within the oral cavity which arenot subjected to such pressure.

In contrast to this situation, when an individual who, for example, isusing full upper and lower dentures, exerts abnormal pressure at arestricted locality against one or more teeth of the denture indicent tobiting or chewing food or the like, such pressure is transmitted to theentire denture or at least to an extensive section of a denture, and,consequently, to the gingival tissue which underlies the same. To thisextent, therefore, it is not feasible at present for the manufacturersof artificial teeth, nor for dentists and dental technicians, whofabricate dentures, to reproduce by artificial means the individualshock-absorbing membrane which surrounds the root portions of naturalteeth, and thereby, eliminate the transmission of shock resulting fromforces imposed against a single or limited number of teeth to the otherteeth in a natural dentition.

it is therefore, the phenomenon described above of each tooth in anatural dentition having its own shockabsorbing membrance to support itwhich renders the natural mastication of food more comfortable thancorresponding mastication of food by dentures and especially full upperand lower dentures. Thus, in an effort to minimize the imparting ofshock to at least similar opposing entire sides or sections ofartificial upper and lower dentures, incident to masticating food whichrequires the exertion of normal forces or forces greater than normal,and correspondingly, to minimize the transmission of such shock to thegingival tissue engaged by the dentures, a number of attempts have beenmade heretofore in the dental profession to minimize such exertion ofabnormal forces required to masticate food by devising variousmechanical innovations in posterior artificial teeth for dentures. Thesehave been essentially in the form of various types of incising means,whereby the posterior teeth have similar incising characteristics to theanterior teeth of a natural dentition. Thus, whereas natural posteriorteeth do not particulary have incising means, it has been proposed toinclude incising means on artificial posterior teeth, in order to severand decimate food when engaged between upper and lower posterior teethembodied in dentures. Typical examples of such innovation are asfollows:

U.S. Pat. No. 2,717,45 to Ford, issued Sept. 13, 1955, illustratesinter-related upper and lower posterior teeth having closed sulci inboth the upper and lower posterior teeth, which effect certain types ofshearing action upon food, but the food is trapped in the closed sulciin view of the fact that no sluice type discharge openings are provided.

US. Pat. No. 3,305,926, to Gerber, issued Feb. 28, 1967, includes aridge on either the lower or upper posterior teeth and a cooperatingconcave surface on the opposite teeth, but no food retaining andshearincluding sulci are provided so as to produce desirable shearingaction.

US. Pat. No. 3,252,220, to Goddard, issued May 24, 1966, includessimilar incising ridges on both the upper and lower teeth whichcooperate with transversely extending grooves that are closed at theopposite ends, whereby sheared food cannot be readily removed therefromdue to no discharge openings or slots being provided.

It will be seen from the foregoing discussion of certain examples of theprior art that even though ridges which are somewhat of an incisingnature have been provided in previous attempts to effect incising offood by posterior teeth, such incising has been inefficient due toinability to effect a desirable shearing action, such as is possible byemploying the same in conjunction with sulciarranged in the oppositetooth from that which has the incisal ridge thereon so as to cooperatewith said ridge in shearing of food when the ridge is moving intransverse excursions across the sulci to shear in one direaction andsluice the sheared food in discharging manner when the incising ridge ismoving in the opposite direction.

SUMMARY OF THE INVENTION It is the principal object of the presentinvention to minimize the pressure required in a masticatory stroke toincise and masticate food by artifical posterior teeth by providing anincising bar on upper posterior teeth which operate against a concavefood table on the opposing lower posterior teeth which is oriented tothe natural movements of the mouth in lateral excursion, said foodtables having elongated sulci extending substantially in buccal-lingualdirections to provide sluiceways to effect shearing action in oneexcursion direction of said incising bar and discharge the sheared foodwhen moving in the opposite excursion direction during reciprocallateral movement of the lower denture relative to the cooperating upperdenture, whereby thre'e cooperative functions are provided; incising,shearing and discharging after temporarily holding the food againstlateral movement of any appreciable extend while the first two functionsare being performed.

It is a further object of the invention to arrange the patterns andshapes of the aforementioned sulci in the lower posterior teeth in sucha manner as to provide a food holding function to enhance the foodshearing functions set forth above, without impeding the discharge ofsheared food from the sulci after shearing has occurred.

It is a further object of the invention to utilize the aforementionedincisal ridge upon the upper posterior teeth and position the samebetween the buccal and lingual sides thereof in such a manner that anytendency for the incising function of the upper teeth to tilt withrespect to the lower teeth is minimized, thereby providing stability ofthe dentures in the masticating functions, and consequent comfort to thewearer.

It is still another object of the invention to provide a design of sulciin the occlusal surfaces of both the upper and lower posterior teethwhich have a some what natural appearance similar to occlusal surfaceson natural or artificial teeth which actually inter-digitate, yet theteeth comprising the present invention offer no interference in anyexcursion between the cooperating dentures in masticatory operation,whereby the teeth offer similar advantages to those afforded byso-called flat plane teeth with respect to easier fabrication of thesame into finished dentures than is possible with artificial teethhaving inter-digitating occlusal surfaces.

It is still another object of the invention to provide pairs ofcooperating posterior artificial teeth in which, as a result of simpleaxial movement toward each other, the incising ridge on the upper toothcoacts with the concave food table on the lower tooth to incise food,while during lateral excursions between the upper and lower teeth whenin engagement with each other, actual mastication of the food occurs dueto lateral shearing thereof, while trapped momentarialy in the closedends of the sulci in the lower tooth by the transverse wiping of theincising bar past the closed end of such sulci, thereby effectingfunctions closely resembling those achieved by natural posterior teethwhile the open ends of the same sulci permit ready discharge of shearedfood when the incising bar moves in the opposite lateral direction.

Details of the foregoing objects and of the invention, as well as otherobjects thereof, are set forth in the following specification andillustrated in the accompanying drawings comprising a part thereof.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view throughan exemplary set of upper and lower dentures in which pairs of opposingposterior teeth embodying principles of the present invention aremounted operatively and are shown in centric position.

FIG. 2 is an enlarged end view of a cooperating pair of upper and lowerposterior teeth embodying the invention illustrated in centric position.

FIG. 3 is a view similar to FIG. 2 but showing the upper tooth has movedto the right with respect to the lower tooth as viewed in said position.

FIG. 4 is a top plan view of the lower tooth of each pair shown in FIGS.1-3 to illustrate the various exemplary sulci embodied in the concavefood table surface of said tooth, which comprises the occlusal surfacethereof.

FIG. 5 is a plan view of the occlusal surface of the upper tooth of eachpair of teeth illustrated in FIGS. 1-3 and showing the incising barwhich extends transversely of said surface between the opposite mesialand distal sides of the tooth, and also showing additional food-holdingsulci which are formed on said occlusal surface at opposite sides ofsaid incising bar.

FIG. 6 is a perspective view of one of the lower teeth shown in FIGS.1-3 and illustraing the concave food table or occlusal surface thereofand the buccal side surface to illustrate the life-like appearance ofthe tooth for esthetic purposes.

FIG. 7 is a perspective view of the upper teeth of each pair shown inFIGS. 1-3 showing the occlusal surface which has the incising barthereon, and the buccal surface of the tooth to illustrate the esthetic,life-like characteristics of the tooth.

FIG. 8 is a top plan view of the occlusal surface of the lower teethshown in FIGS. 1-4 and including an imaginary line extendingtransversely between the mesial and distal sides of a tooth whichrepresents the position of the incising bar of the upper tooth whenmoving in a lateral excursion in one direction from another imaginaryline representing the centric position of said bar to sluice shearedfood from the open ends of the sulci and sheared food trapped in theclosed ends or diagonally extending portions of other sulci.

FIG. 9 is a view similar to FIG. 8 but showing the imaginary linerepresenting the incising bar extending transversely between oppositesides of the lower tooth when moving in the opposite excursion directionfrom an imaginary centric position line to illustrate the sluicing ofsheared food from the open ends of certain of the sulci, while shearingfood which is trapped in the closed ends of other sulci.

DETAILED DESCRIPTION For purposes of illustrating the function anddetails of the posterior teeth which embody the present invention, FIG.1 shows an exemplary transverse sectional view of mating denturescomprising an upper denture 10 and a lower denture 12. It will beunderstood that the lower denture 12 is unitary since the illustratedsection is taken near the inner end of the denture as used in the mouth,such denture in plan view being substantially U-shaped. The upperdenture is provided with a pair of posterior teeth respectivelycomprising a left upper tooth 14 and a right upper tooth 16. The lowerdenture has a pair of exemplary lower posterior teeth mounted thereonrespectively comprising a left lower tooth l8 and a right lower tooth20. As viewed in FIG. 1, the sides of the teeth which are foremost themesial sides thereof. It is also to be understood the the presentinvention pertains to all posterior teeth, including bicuspids andmolars. For simplicity, however, only pairs of upper and lower molarteeth are shown in the drawings and described in detail hereinafter.

The upper posterior teeth 14 and 16 are provided with incising ridges 22which extend in a mesial-distal direction intermediately between theopposite buccal and lingual sides of the occlusal surfaces of the teeth.Referring particularly to FIG. 5, such sides of said teeth are indicatedin exemplary manner by appropriate numerals. Thus, in FIG. 5, the buccalside 24 is opposite the lingual side 26 and the mesial side 28 isopposite the distal side 30. The occlusal surface of the upper teeth 14and 16 is provided with a plurality of irregularly shaped cusps 32 and34 respectively which are partially surronded by irregularly shapedsulci 33 and 35 which are respectively positioned at opposite sides ofthe incising bar 22.

Sulci 33 and 35 have a mechanical function of holding the food fromappreciable lateral movement with respect to the incising bar 22incident to generally axial movement thereof toward the arcuate foodtable 36 comprising the occlusal surface of the lower posterior teeth 18and 20. In addition, the sulci 33 and 35 provide cuspal effectstherebetween with respect to the lowermost projecting areas thereofwhich aid in the food retention function described above. In addition,they provide anatomical esthetic effects. Still further, sulci 35' whichare somewhat crescent shape are arranged outwardly from cusps 32. Also,distributed on opposite sides of the incising ridge 22, are a pluralityof flat crushing surfaces 35" which slope downwardly from ridge 22 tobrace the bar comprising the ridge 22 and also act as a plow through thefood being incised by the ridge.

The lower posterior teeth 18 and 20, as indicated above, have occlusalsurfaces comprising the arcuate food table 36 which is oriented relativeto the natural movements of the lower jaw in lateral excursion, saidcurvature extending buccal-lingually between the buccal side 38 and thelingual side 40 of said teeth. The

axis of the arc which defines the food table 36 extends between themesial side 42 and the distal side 44 of the lower posterior teeth 18and 20.

The arcuate food tables or occlusal surfaces 36 of the lower posteriorteeth 18 and are provided with elongated sulci 46 which are closed atends that are nearest the buccal side 38, but are open adjacent thelingual side 40. Said occlusal surface 36 also is provided with at leastone additional elongated sulci 48 which is closed at the end that isnearest the lingual side 40 of the tooth but is open at its opposite endwhich is nearest the buccal side 38 of the tooth.

There is a further irregular sulci 56 which is somewhat zig-zag in shapeand is open at its opposite ends respectively adjacent the buccal 38 andthe lingual side 40. In addition, there is a still further irregularsulci 52 in the arcuate food table surface 36 of each of the lowerposterior teeth 18 and 20 which has a somewhat aiz-zag irregular portionitermediately of the ends thereof, the opposite ends of said sulcirespectively opening in opposite directions into the elongated sulci 48and the lingual side 40 of the tooth.

The function of the particular shapes of the various elongated sulci 46,48, 5t) and 52 is twofold, one of these functions being to trap and holdthe food during relative lateral movement of the lower tooth relative tothe upper tooth upon which the incising ridge or bar 22 is positionedand the other function is to coact with incising bar 22 to effectshearing of food. For example, in FIG. 8, one such relative lateralmovement between the teeth causes the bar to move from the imaginarycentric position indicated by the line 54 to a position where the bar orridge 22 is nearer the lingual side 40 of the lower tooth 18 or 20. itwill be seen that a bolus of food 56 is held or trapped within theclosed end portion of the sulci 48. Also, a certain amount of food isheld or trapped within the angularly extending sulci 58 and 60 whichjointly comprise the discharge ends of the elongated sulci 46. In suchrelative movement, it will be assumed that the direction issubstantially in a transverse direction to the incising ridge or bar 22and the holding of the food by the closed end of sulci 48 and theangularly extending sulci 58 and 60 permits the incising ridge or bar 22to slidably move along the curved portions of the arcuate food table 36which intervene the various sulci and, in so doing, effects a shearingoperation of the food which is held in sucli 48, 58 and 60.

A second function of the sulci is that, during such aforementionedmovement between the upper and lower teeth, as the lingual side 40 ofthe loer tooth is moved toward the ridge or bar 22, additional bolusesof previously sheared food 62 are discharged in a sluicing manner fromthe open ends of the various sulci as clearly illustrated in FIG. 8.Therefore, it will be seen that such relative movement effects both ashearing function with respect to food retained either in angularlyextending sections of the sulci or the closed ends thereof, while foodthat has been previously sheared by a similar function in previousexcursions in the oppositely opening sulci is sluiced from the open endsthereof.

The illustration in FIG. 8 is intended to depict rela tive movementbetween the upper and lower teeth in one direction. In FIG. 9, however,similar relative movement in the opposite direction is illustrated and,in said figure, it will be seen that boluses of food 64 are held ortrapped within the closed end portions of sulci 46. Therefore, theboluses are being sheared by engagement therof with the incising ridgeor bar 22, while additional boluses of food 66 which have previouslybeen sheared in the opposite excursions, are being discharged in asluicing manner from the open ends of sulci 48, 50 and 52. Discharge isalso occurring from intermediate sulci 63 which opens freely adjacentthe buccal side 24 of the tooth, but has a corresponding constrictedopening 70 at the end adjacent the lingual side 40 of the tooth. Thelatter also cooperates with ridge 22 to effect shearing when the ridgemoves toward lingual side 26 of teeth 18 and 20.

It will be understood that the various excursions which respectivelyeffect either shearing or sluicing discharge of boluses of food will notalways result in complete discharge of food from the sulci, especiallywhen moving in sluicing discharge direction relative to the incisingridge or bar 22. Small amounts of the food may remain in the sulci untilperhaps the next excursion or the one after that will ultimately removethe food after reasonably adequate shearing has occurred.

From the foregoing, therefore, it will be seen that the presentinvention provides posterior teeth having cooperating occlusal surfaceswhich greatly enhance the comfort factor to a patient who, inparticular, wears full dentures. This is accomplished by providing anincising ridge or bar which when moving in direct axial direction towardan arcuate food table in the opposite tooth effects actual incising offood to initiate the mastication thereof, the food also being preventedfrom migrating materially from opposite sides of the incising ridge orbar by providing restraining sulci 32 and 34 which are formed in theocclusal surface of the tooth which carries the incising ridgeor bar 22.By providing such ridge or bar 22, pressure necessary to effect incisingof the food is minimized in contrast to other artificial teeth whichemploy no such incising ridge or bar.

Following the incising function, the subsequent lateral excursionmovements which are effected in the course of natural mastication offood by natural move ments of the mouth in lateral excursions causesboth shearing of boluses of food which are restrained by certain sulciagainst lateral movement while the incising bar or ridge moves thereoverand shears the food, followed by sluicing type discharge of the shearedfood when opposite lateral movements between the teeth are effected.Accordingly, it is apparent that three principal beneficial functionsare effected by the present invention, namely, incising of the food byan actual incising ridge or bar, shearing of the food in a transversedirection while the food is prevented from moving laterally appreciablywhen engaged by the incising bar or ridge during lateral excursionmovement in one direction, followed by sluicing type discharge of thefood when the lateral excursion movement is effected in the oppositedirection.

All of the foregoing contributes greatly to comfort in the use ofdentures and minimizes the amount of pres sure which normally isrequired in denture use to masticate food satisfactorily. In addition tothe functional aspect of the preferred arrangements of the sulci in boththe upper and lower teeth, they and the other exterior surfaces of theteeth are so designed that they resemble the charastistic appearance ofnatural posterior teeth, while functioning similarly to flat planeteeth. Thus, they greatly facilitate the fabrication of dentures withoutrequiring complicated articulation of the teeth,

such as is required in the fabrication of dentures employing cusp-typeteeth which function mechanically similarly to natural teeth.

Not only is the fabrication of dentures with teeth embodying the presentinvention facilitated, but from the esthetic standpoint, the arrangementof sulci as described above in the teeth of the present inventionproduces a natural and life-like appearance in the teeth, in addition togreatly improving the mechanical functioning thereof, whereby there isnot only increased physical comfort to a person wearing dentures, butpsychologically, there is also the peace of mind resulting from minimumpossibility of detection that a person is wearing dentures, due to thelife-like appearance of the teeth embodying the present invention.

While the invention has been described and illustrated in its severalpreferred embodiments, it should be understood that the invention is notto be limited to the precise details herein illustrated and describedsince the same may be carried out in other ways falling within the scopeof the invention as illustrated and described.

I claim:

l. A pair of cooperating posterior artificial teeth for application toartificial dentures and adapted respectively to be mounted in the upperand lower denture and said teeth each having ridge lap surfaces adaptedto be affixed to denture base material, the tooth for the upper denturehaving an incising ridge intermediately of its buccal and lingual sidesextending in a substantially mesial-distal direction on the occlusalsurface and the lingual and buccal side edges of said surface beingsmoothly rounded outwardly and toward the ridge lap end of the tooth toproduce a natural posterior tooth appearance, and the other tooth ofsaid pair having an occlusal surface which is generally concaved in abuccal-lingual direction, said concaved surface also having a pluralityof sulci extending substantially transversely of said tooth for adistance greater than half the width of the tooth in a buccal-lingualdirection and closed at one end to effect a shearing action with saidincising ridge, the opposite ends of said sulci opening outwardly of oneedge of said occlusal surface of said tooth to provide means forsluicing discharge of a bolus of food which has been incised and shearedduring relative occlusal movement of said teeth in buccal-lingualdirections.

2. The teeth according to claim 1 in which said sulci in said othertooth alternately open to the opposite side edges of said occlusalsurface, whereby both shearing and sluicing of food therefrom occurs ineach direction of relative movements between said upper and lower teethin buccal-lingual directions.

3. The teeth according to claim 1 in which the concavity of the occlusalsurface of said other tooth is substantially on an are described by thelateral excursion movements of said incising ridge of said one toothduring relative buccal-lingual movements between said teeth.

4. The teeth according to claim 1 in which said tooth for the upperdenture also is provided with sulci in opposite sides of said incisalridge to maintain integral balance of the ridge relative to the sulci onsaid other tooth to implement the shearing.

1. A pair of cooperating posterior artificial teeth for application toartificial dentures and adapted respectively to be mounted in the upperand lower denture and said teeth each having ridge lap surfaces adaptedto be affixed to denture base material, the tooth for the upper denturehaving an incising ridge intermediately of its buccal and lingual sidesextending in a substantially mesial-distal direction on the occlusalsurface and the lingual and buccal side edges of said surface beingsmoothly rounded outwardly and toward the ridge lap end of the tooth toproduce a natural posterior tooth appearance, and the other tooth ofsaid pair having an occlusal surface which is generally concaved in abuccal-lingual direction, said concaved surface also having a pluralityof sulci extending substantially transversely of said tooth for adistance greater than half the width of the tooth in a buccal-lingualdirection and closed at one end to effect a shearing action with saidincising ridge, the opposite ends of said sulci opening outwardly of oneedge of said occlusal surface of said tooth to provIde means forsluicing discharge of a bolus of food which has been incised and shearedduring relative occlusal movement of said teeth in buccal-lingualdirections.
 2. The teeth according to claim 1 in which said sulci insaid other tooth alternately open to the opposite side edges of saidocclusal surface, whereby both shearing and sluicing of food therefromoccurs in each direction of relative movements between said upper andlower teeth in buccal-lingual directions.
 3. The teeth according toclaim 1 in which the concavity of the occlusal surface of said othertooth is substantially on an arc described by the lateral excursionmovements of said incising ridge of said one tooth during relativebuccal-lingual movements between said teeth.
 4. The teeth according toclaim 1 in which said tooth for the upper denture also is provided withsulci in opposite sides of said incisal ridge to maintain integralbalance of the ridge relative to the sulci on said other tooth toimplement the shearing.